BACKGROUND: Hypoxemia is common in patients with cirrhosis but the natural history of this syndrome is unknown. This study was conducted to evaluate the natural history of arterial oxygenation in patient with end stage liver cirrhosis.METHODS: Sixty eight patients with liver cirrhosis were followed up for 6-12 months. Arterial blood gas (ABG) and pulse oximetry were obtained on day of presentation and follow up.RESULTS: There were no significant changes in the oxygen saturation by pulse oximetry (SpO2), partial pressure of oxygen (PaO2) and alveolar arterial oxygen gradient (A-a O2) after 6-12 months. Mean arterial oxygen saturation (SaO2) in 46 patients was 95.42±1.92, and after follow up changed to 95.45±2.96. Thirty eight patients had SaO2 > 94% (mean 96.12±1.08 after 6-12 months changed to 95.66±2.58) ; 8 patients had SaO2 = 94 (mean 92.08±1.44 after 6-12 months changed to 94.46±4.47).CONCLUSION: There were no significant changes in the SpO2, PaO2 and A-a O2 after 6-12 months.